Manhole-frame



flo. 689,224. Patented nec. |7,-1'9u|.

- E; c. PILLsBunv.

IINHOL FHAIE.

(Application lsd June 15, 1901.)

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Patented Dec.- I7, 90L

nu. 689,224. y

F. C. PILLSBURY;

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WTNEESES.

UNITED STATES? PATENT FFICE.

FRANKLIN C. PILLSBURY, "OF 'WINCHESTEl MASSACHUSETTS.

MANHOLE-FRAM E.

SPECIFICTIO forming part of Letters patent No. 689,224, dated December 17, 190i.

Application filed June'l, 1901.

To all whom it may concern:

Be it known that I, FRANKLIN C. PILLS-l BURY, of Winchester, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Manhole-Frames, of which the following is a specification. i

This invention relates to manholeframes which surmount or cap streetmanholes in sewers and other underground conduits and are provided with removable covers, the upper edge of the frame and the upper surface of the cover being substantially flush withy the surface of the` street in which the manhole is located. It not infrequently happens that owing to `changes in'grade or depression of the street-surface by wear the upper edge of the frame and the upper surface of the cover as originally adjusted are either raised above or depressed below the street-surface and require adjustment, it being desirable that theupper edge of the frame and the u pper surface of the cover constitute parts of.

the street-surface without being either'raised above or depressed below the surrounding surface.

My invention has for its object to make the cover and the cover-supporting portion of a manhole-frame vertically adjustable to compensate for changes' that maytake place in the level of the surrounding surface of the street.

To this end my invention consists in a manhole-frame which is extensible or telescopic in construction and comprises an annular fixed base member which rests on the masonry portion of the manhole and is nonadjustable and an annular movable member which supports the cover and is adapted to be rotated in the base member, said members being provided withmeans whereby the rotation of the movable member variesits heightl Von'the masonary of a'manhole.

Serial No. 64,677. (No model.)

ber, the movable member heilig shown in dotted lines; Fig. 4 represents a perspective view of the movable member, the base member bc- `ingshownin dotted lines.

The same reference characters indicate the same parts in all the figures.

`In the drawings, a represents the annular base member of my extensible manholeframe, said member having an outwardlyprojecting ange 2 at. its lower edge to rest On the inner surface of the member ct are formed a series of segments 3 of a helical rib -or cam, three of such segments being shown in the present case, each being the equivalent of apart of a screw-thread.

b represents the movable member of the frame. This member is of considerably less diameter than the member a, so that it can occupy the space surrounded by the segments 3. On the outer surface of the movable member b are formed a series of segments 4, which are complemental to the segments 3, but are considerably shorter, the segments 4 bearing on the segments 3 and being inclined to conform to thepitch ofthe latter. The inclinaltion or pitch of the segments 3 and 4 is such that when the member b is rotated the segments will cooperate in raising or lowering the member b, according to the direction of rotation. The segments 3 and 4 are provided with means, such as interlocking projections 5 and recesses 6, whereby they may be locked together to prevent accidental rotation of the member b, so that before said member can be rotated and vertically adjusted it is necessary to raise it suiciently to disengage the segments 4 from the segments The member b has an inwardly-projecting shoulder 7, which forms a seat for the marginal portion of the manhole-cover, the upper surface of the cover being flush with the upper edge of. the member b. The member ct is preferably provided with a narrow inwardly-projecting lip or flange S, which .partially covers 'the space between the members a and b and prevents the entrance of pebbles, te., to said space.

9 represents a stop-l ug formed on the flange 8 to abut against the highest segment 4 on the movable member when said member has reached the limit of its upward adjustment,

IOO

y threadvor helical cam-sections on the inner `the outer surface of the movabley member the said stop-lug preventing further rotation of the movable member in the direction frequired to adj ustl it upwardly. The segments 4 are thus prevented from moving off from the higher ends of the segments 3. o

10 10 represent stop-lugs formed at the lower ends of the segments 3 to limit in like manner the movement of the member b in the direction required to adjust it downwardly.

I claiml. An extension or telescopic frame comprising an annular fixed base member, an annular movable member, elongated screwthread or helical cam-sections ou the inner surface of the xed member, and complemental screw-thread or helical cam-sections on supported by the sections of the fixed member, whereby a rotary movement of the movable member varies its height relatively to the fixed member, said cam-sections having provisions for locking the two members together to prevent accidental rotary movement of the movable member.

2. An extension or telescopic frame comprising an annular fixed basemember, an annular movable member, elongated screwsurface of the fixed member, and complemental screw-thread or helical cam-sections ouf the outer surface of the movable member supported by the sections of theyfxed meni-V ber, whereby a rotary movement of" the movable member varies its height relatively to the fixed member, said sections having interlocking projections and recesses, whereby rotation of the movable member is prevented when the sections are interlocked, the sections of the movable member being separable from those of the xed member to permit the adjustment of the movable member.

3. An extension or telescopic frame comprising an annular Iixed base member, an annular movable member, elongated screwthread or helical cam-sections on the inner surface of the fixed member, and complemental screw-thread or helical cam-sections on the outer surface of the movable member supported by the sections of the fixed member, whereby a rotary movement of the movable member varies its height relatively to the fixed member, the fixed memberhaving inwardly projecting stops arranged to abut against the higher ends of the cam-sections on the movable member and limit the upward rotary movement of the movable member.

In testimony whereof I have alixed myfsigi nature in presence of two witnesses.

FRANKLIN C. PILLSBURY.

Witnesses:

A. B. FLETCHER, E. J. OHARA. 

